Work conveying mechanism for furnaces



April 8, 1952 M. BLOOM WORK CONVEYINGMECHANISM FOR FURNACES 5 SheetsSheet 1 Filed July 15, 1950 FIG. I

INVENTOR. QUENTIN M.BLOOM ATTORNEY.

April 8, 1952 Q. M. BLOOM WORK CONVEYING MECHANISM FOR FURNACES 5 Sheets-Sheet 2 Filed July 15, 1950 FIG.5

ATTORNEY.

April 8, 1952 Q. M. BLOOM 7 WORK CONVEYING MECHANISM FOR FURNACES 3 Sheets-Sheet 3 Filed July 15, 1950 INVENTOR. QUENTIN M. BLOOM ATTORNEY.

Patented Apr. 8, 1952 WORK CO NVEYING MECHANISM FOR FURNACES Quentin M. Bloom, Huntingdon Valley, Pa., assignor to Selas Corporation of America, Philadelphia, Pa., a corporation of Pennsylvania Application July 15, 1950, Serial No. 174,009

'7 Claims. 1

The present invention relates to apparatus for heating large billets, and more particularly to apparatus for conveying large, heavy billets through a furnace or other device while the billets are being heated or being moved from one point to another.

The heating of large billets for piercing or other purposes has heretofore usually been done in rotary hearth or roller hearth furnaces. Even with furnaces of this type the handling of the heavy billets, which may weigh as much as three and one half to four tons, is a problem that has occasioned much difiiculty.

In accordance with the present invention large billets that may be as much as thirteen'inches in diameter and sixteen feet long are heated individually in substantially cylindrical furnaces. The billets are moved one after the other in end to end relation. The furnace may be continuous or made in sections as desired, and depending upon the length thereof that is required to bring the billets up to the desired temperature. In some cases it may be desirable to provide a preheating chamber above the heating chamber and connected therewith by passages through which products of combustion may pass. In such a case the billets are moved in one direction through the preheating chamber, and in an opposite direction through the heating chamber.

The mechanism formoving the billets through the preheating chamber may comprise conventional conveyor rollers of heat resistant material. The mechanism for moving the billets through the heating chamber, however, comprises a number of rotating shafts with their upper ends extending through the floor of the furnace. These shafts are spaced at intervals throughout the length of the furnace and are provided with caps upon which the billets rest. As the shafts are rotated the billets are moved axially through the furnace. By mounting the shafts at an angle to the vertical in the direction of billet movement the billets will be rotated around their axes as Well as being moved axially. This construction is such that a minimum number of openings is made through the furnace wall for the conveying mechanism. Equally as important is that the billets are being supported only at a plurality of points so that they may be evenly heated. There is an absolute minimum contact between the billets and their supporting and conveying mechanism.

It is an object of the invention to provide a furnace in combination with means to move work. to be heated through the furnace. It is a further object of the invention to provide mechanism to move work through a furnace, which mechanism has a minimum of contact with the work while it is being heated.

Another object of the invention is to provide means to convey an elongated object through a path by mechanism including parts that engage the work at a plurality of spaced points. A further object of the invention is to provide mechanism to rotate elongated objects around their axes as they are being moved through an axially disposed path.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings:

Figure 1 is a section through the furnace taken on line l| of Figure 2;

Figure 2 is a section through the furnace taken on line 2-2 of Figure 1;

Figure 3 is a section of the furnace taken on line 3-43 of Figure 2;

Figure 4 is a view in section showing the details of the conveying mechanism;

Figure 5 is a section of the furnace corresponding to Figure l, and taken on line 55 of Figure 6, but having a modified form of conveying mechanism; and

Figure 6 is a view from the right of Figure 5.

Referring to the drawing, there is shown a furnace I having an elongated heating chamber 2 through which the work W, shown herein as cylindrical billets, is passed. The furnace may be provided with a second chamber 3 in which work is preheated, and is shown herein with such a chamber located directly above the chamber 2. The furnace may be either a single elongated chamber or may consist of a number of units placed end to end. Work is moved through the preheating chamber by means of conveyor rolls 4 mounted on shafts 5 that extend through the sidewalls of the chamber and which are supported in suitable bearings. These shafts may be either perpendicular to the line of travel of the billets or at a slight angle to the perpendicular. In the latter case, the skewed rollers will cause the work to be rotated around its axis as it is being advanced through the preheating chamber. In some cases this is desirable since the work can often be more evenly heated around its periphery if it is rotated as it is passing through the furnace.

The furnace is constructed of refractory material 1 in accordance with usual furnace practice, which refractory is backed up by sheet metal work 8. The entire furnace is rigidly held in position and supported by structural steel members 9. It will be seen that the heating chamber 2 is shaped so that it closely surrounds the work being heated and is provided on each side with a row of burner blocks I I that are directed toward the work. Each of these burner blocks forms a part of a burner of the type disclosed in the application of A. A. Furczyk, Serial No. 56,616, filed on October 26, 1948, now Patent No. 2,561,793 issued July 24, 1951. These burners are of the radiant type and are provided with cup-shaped depressions |2 into which the end of a distributor is extends. A suitable mixture of gas and a combustion supporting gas are supplied through the distributor and from which they are discharged in a substantially radial direction into the cup. The fuel mixture is ignited as it leaves the distributor and burns within the cup to heat the same to'incandescence. The burners are so designed that complete combustion takes place within the cup so that flame will not, impinge upon the work. Radiant heat is directed from the incandescent cups l2 toward the work, andthis heat is augmented by convection heat produced b the hot products of combustion which circulate around the work in a highly turbulent condition. Some of the hot products of combustion are discharged through entrance and exit openings M at the ends of the furnace chamber 2. Most of the hot products of combustion, however, are discharged through the openings |6 into the preheat chamber 3 in order to preheat the work moving through that cham ber.

The openings M at the end of the furnace are of a diameter smaller than the diameter of the furnace chamber and slightly larger than the maximum diameter of the billets that are to be heated. These openings may .well be faced with a water-cooled jacket |5 that will serve to protect the ends of the furnace from the action of the hot products of combustion which are blasted through this opening. It is noted that the roof of-the preheating chamber 3 is formed of slabs .l'l which can be removed togive access to this chamber and, through the openings l6, to the chamber 2. It is also noted that the floor of the chamber 2 is provided with a plurality of openings 2| through which the work forwarding or conveyor mechanism shown generally at 22 may extend into the furnace chamber. This conveyor mechanism is used to move the work axially through the heating chamber 2 and is of a novel construction. The conveyor mechanism will now ,be described.

The mechanism for moving the work through the heating chamber of thefurnace includes a plurality of upstanding members 23 made of heat resistingalloy and each of which has a cap 24 on the upper end thereof upon which work is supported. It will be seen that these members extend from below the furnace and into chamber 2 through the openings 2| in the bottom of the chamber. The openings 2| need be only large enough to receive the members, which are set at an angle of approximately to the vertical as shown in Figures 1 and 4. The members, however, are substantially vertical in a direction at right angles to the length of the furnace cham-- her as shown in Figure 2. From an inspection of Figure 3 it will be seen that the members 23 are placed in two parallel rows through the furnace chamber and that the members of each row are staggered with respect to the members in the other row. The members 23 can be spaced at any necessary interval. On a furnace designed to handle billets of a minimum of six feet in length the members will be spaced on two foot, ten inch centers so that each billet will at all times be supported on at least four of the members, two in each row.

Each of the members 23 projects from and is mounted for rotation in a gear box 25 taking the form of a housing that is in turn supported on structural members 26 below the furnace. Referring to Figure 4 it will be seen that the lower end of member 23 is provided with a flange 21 that rests against a flange 28 attached to a hollow shaft 29 and is axially aligned with the shaft. The flange 2 8 is preferably welded to the shaft 29 but may also be maintained against rotation with respect thereto by a suitable key such as that shown at 3| in the drawing. The member 23 is held in position on the shaft by means of a split collar 32, each half of which surrounds the member and is attached by bolts 33 to flange 28. In order to prevent relative rotation between the member and. its driving shaft, keys 34 are fastened by set screws 35 to the halves of the collar. These keys are received in suitable key ways that are formed in the lower end of member 23 just above the flange 21. A skirt 36 is attached to the periphery of the flange 28 by means of suitable screws 31. This skirt acts to protect the supporting parts for member 23 and to prevent any possibility of scale or dirt which may fall through the opening 2| of the furnace from getting into the driving mechanism for the supporting member. The upper end of shaft 29 is reduced as shown at 3B in the drawing to receive the lower end of member 23 and to guide the same into place as it is being lowered into position through the openings H5 and 2| of the furnace.

Shaft 29 is guided at its upper end in the housing 25 of the gear box by means of a bearing 39 that is protected from above by a cap 4|. This cap is attached to the housing by bolts 42. It is noted that the shaft 29 has oil seal rings 43 between it and the cap. These rings protect the shaft from dust that may otherwise get into the housing, and also act to retain oil that is sprayed into the housing and over the bearing 39. The lower end of the shaft 29 is guided by and the end thrust of the shaft is taken up by a bearing 44 that is placed on a reduced portion 45 of the shaft. This bearing is held in place on the shaft by a sleeve 46 that is threaded on the lower reduced end of the shaft, with the upper end of the sleeve engaging the inner-race of the bearing to hold the same against the shoulder formed on the shaft where the reduced portion 45 terminates. The lower end of the housing through which the shaft extends is closed by an annular plate 48 which is held in position by bolts 49. During the operation of the device oil for lubricating the bearings and the driving gears to be described is forced into the upper part of the housing at 53 with the lower portion of the housing including the cap 43, forming a sump into which the oil can be collected for recirculation. To this end the sleeve has a downwardly ex- I tending portion which serves somewhat to prevent oil from flowing between the plate 48 and the shaft. In addition, there is provided an oil seal 5| in the lower face of the plate 48 to prevent any loss of oil.

The drive for each of the members 23 in each of the units is obtained from a driving shaft 51 that extends through the housing in the direction of the furnace chamber. This shaft is journalled in bearings 52 and 53 on each side of the housing and is provided on each end with a coupling 54 that can be connected to similar shafts in the adjacent units. A suitable motor is provided to drive the shafts so that all of the members 23 throughout the length of the furnace are driven at the same speed. The arrangement is such that shaft 5| has a helical gear 55 on it which meshes with and drives two gears 56, one of which is on each of the shafts 29. The gear 56 is keyed to shaft 29, and is held in position axially of the shaft 29 by a sleeve 51 which extends between the gear and the upper bearing 39 and a sleeve 58 which extends between the gear and the lower bearing M. These sleeves not only serve to locate the gear 56 on the shaft 23, but also to absorb the thrust of the gear and transfer it to the bearing. It will be seen that the two gears 56 and shafts 29 in each unit will be driven in opposite directions. This means that the members 23 in one row, in Figure 3 for example, will be rotated clockwise while the, members 23 in the other row will be rotated counterclockwise. Therefore, a billet resting as shown in Figure 2 partially on members in both rows will be moved axially through the furnace.

Since the cap 24 and the upper end of the member 23'extend into the furnace and are subjected to the heat thereof, it is advisable to watercool these parts. For this purpose the lower end of shaft 29 has a rotary union 59 fastened to it. The union is provided with an inlet pipe 61 through which a suitable coolant may be supplied thereto and an outlet pipe 62. This outlet pipe is connected in the union with a pipe 63 that extends axially of the shaft 29 to the upper end thereof where it is held in concentric relation with shaft 29 by a spider 34. Threaded into the upper end of the spider is a pipe 65 forming a continuation of pipe 63 that extends to the upper end of the member 23 as is shown in the drawing, Therefore, as the coolant, which is usually water, is introduced through the inlet 6|, it will flow upwardly in shaft 29 and member 23 into the cap 2 1. From here the water will flow back through pipes 65 and 63 to the outlet pipe 62. The amount of cooling that is obtained will depend both upon the volume of water supplied through the member as well as the height of the pipe 65. The nearer this pipe is to the inside surface of the cap 24 the more the latter will be cooled.

Referring to Figure l of the drawing it will be seen that each opening it between chambers 2 and 3 is so spaced that it is in axial alignment with a member 23 of adjacent conveyor units. In assembling or dis-assembling these members with respect to the rest of the apparatus, the top I! of the chamber 3 will be removed. Thereafter the skirt 36 and the split ring 32 will be removed from the shaft 23. A suitable tool can then be inserted through an opening 16 to withdraw one of the members 23 from the furnace. This procedure can be followed with comparative ease when it is necessary to repair the conveying mechanism for any reason. After the members 23 have been removed it is, of course, easy enough to disconnect the couplings 54 and withdraw the housing 25 for repair or replacement. The construction described herein is such that repair and replacement of the various supporting means can be rapidly accomplished with a minimum of disruption of the entire system.

In an installation using furnaces of the type disclosed herein, the furnace can be made as a single elongated structure, but it is usually made in sections or units that are axially aligned with each other. Individual sections are desirable since one furnace section and a conveying mechanism associated therewith may be replaced when the furnace section needs repair or relining, as it will from time to time, without the necessity of shutting down the entire line.

In the operation of a furnace system of the type described herein it is necessary that the billets being heated be at least as long as the distance between three adjacent supporting members 23 that are in the same side of the furnace chamber. The minimum length of-the billets handled will be dependent upon design problems, and will generally be in the neighborhood of six feet. Th maximum length of billets handled, however, would depend entirely upon mill practice. The billets to be heated are placed by some suitable lifting mechanism in axial alignment with the preheating chamber 3 and are moved through that chamber by the rollers 4. During this process they are heated by the products of combustion coming through the open ings l6 from chamber 2. Thereafter the billets are moved to a lower level until they are aligned with the supporting members 23 in the furnace chamber 2. The billets are moved by these supporting members through the furnace chamber 2 where they are brought to the desired temperature. It will be seen that each billet is supported by at least two of the caps 24 on each side of a vertical line through the center thereof as indicated in Figure 2. As the caps are rotated in opposite directions they will act upon the billet and move it axially through the furnace chamber.

In view of the fact that the members .23 are set at an angle to the vertical in the direction of movement of the billet, the billet will also be given a rotating movement around its axis. This can be readily understood because of th vectors involved in the support of the billet at its point of contact with .the caps 24. The construction shown herein permits the handling of an extremely heavy billet with a minimum of apparatus in the furnace itself. Furthermore, since the billet is being moved axially and is being rotated while it is moved, and since the billet is only supported at any one time at a plurality of points on its surface, the billet will be evenly heated throughout its length Without the possibility of.

cold spots or streaks being formed thereon; The present construction reduces engagement of the handling mechanism against the billet to an absolute minimum. In the embodiment of themvention described above the supporting members 23 are fixed atan angle of about 15 to the vertical. This will produce a revolution of 13" diameter billet around its axis in 12.7 feet of linear travel.

In some cases it may be desirable to have the members 23 set at a different angle so that a billet, perhaps of a smaller diameter, will be rotated in a greater or shorter distance of linear travel. -A construction by means of which the supporting members.

supporting members 23 can be adjusted angularly is disclosed in Figures 5 and 6 of the drawing. In this case the supporting members are mounted in bearings in a manner similar to that described above. Here, however, each of the supporting members and its bearing structure is placed in an individual housing H which is rotatable around an axis formed by a driving shaft for each pair of supporting members. This drive shaft is indicated at T2 and has a worm 13 on it meshing with worm gears '55 that are keyed to the hollow shafts 29 upon which members 23 are mounted. Each of the housings is fastened in its adjusted angular position to a center plate 75 that is mounted on the supporting structure 26. The housings are fastened to this plate by means of bolts 16 which extend through ears 11 on the housing. The plate i5 can be provided with holes, or it can be provided with slots through which the bolts extend so that the housing can be adjusted to any angular position within its limits of travel. Each housing is also provided with a downwardly extending arcuate flange 13 that rests upon a track or shoulder F9 forming a part of the center plate 55. The center of the radius of curvature of the tracks are at the shaft 12 so that the housings will be supported on the tracks in any of their adjusted positions.

Referring to Figure 6, it will be seen that the shaft '72 extends from one side of the housing and has a bevel gear 8! on its end which meshes with a bevel gear 82 on a drive shaft 83. This drive shaft extends parallel to the furnace and is supported for rotation in bearings that are mounted on structure 84 which is attached to the furnace supporting foundations. The shaft 83 will be driven by a motor at any suitable speed so that all of the supporting members 23 will be driven at the same speed to forward the work through the furnace at the desired rate.

Since the supporting members 23 are adjustable through an angle it is necessary to have openings 85 in the bottom of the furnace that are long enough to permit the full adjustment of the These openings will permit an undesirably large volume of air to be drawn in through the bottom of the furnace. Therefore, plates 85 having an opening in them through which the supporting members extend are provided at the bottom of the furnace to cover the openings 85. The plates 85 can be mounted in any suitable fashion so that they of the members 23. the members 23 will vary in height somewhat with respect to the bottom of the furnace as they are adjusted to various angular positions.

This variation, however, is not sufficient to change the height of the billet with respect to the burners enough to have any effect on the heating of the billet.

This embodiment of the invention operates in exactly the same manner as the above-described embodiment with the addition that the rotation of the billets during the time that they are being heated can be adjusted from zero when members 23 are vertical to a maximum when members 23 are at their greatest angular position with respect to the vertical. In most cases the angle of the members 23 with respect to the vertical will only be adjusted once for a given size and composition of billets that are being heated. This adjustment will not be changed unless the size of the billet being heated is 8 changed or unless its analysis requires that it be rotated at a different speed. The proper speed of rotation or angle of adjustment of the members 23 can best be determined empirically.

From the above description it will be seen that I have provided a conveying mechanism to move a billet through a furnace while it is being heated, which mechanism contacts the billet at a minimum area of its surface so that substantially the entire billet is at all times exposed to the heat of the furnace. In addition to the above, the construction of the mechanism is such that extremely heavy billets can be handled rapidly and with ease to forward the Work continuously through the furnace while it is being heated, and from the furnace to a point of use such as, for example, a piercing mill.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention, as set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. Apparatus for heating elongated work comprising a furnace having an elongated, horizontally disposed chamber therein, a plurality of burners in the walls of said chamber to supply heat to the work, said furnace having in the bottom thereof a plurality of openings extending into said chamber, said openings being staggered with respect to each other lengthwise of the chamber, work supporting and conveying members extending through said openings with an end of each member in said chamber, the work resting upon the ends of said members, and means to rotate said members around their axes to advance the work through said chamber.

2. In apparatus for heating elongated work, the combination of a furnace having an elongated, horizontally disposed furnace chamber, said furnace being provided with a plurality of parallel rows of openings in the bottom of said chamber, a supporting member extending through each opening into the chamber with the ends of said members terminating adjacent to the floor of said chamber, the work being heated in said chamber resting on said members, and means to rotate the members extending through each row of openings in opposite directions to advance the work through said chamber.

3. The combination of claim 2 in which said members extend at an angle to the vertical in the direction of chamber length.

4. The combination of claim 2 including means to support said members, and means to adjust said supporting means through an angle in the direction of chamber length.

5. Apparatus for heating elongated work comprising in combination a furnace having an elongated chamber through which the work is to be moved, a plurality of burners located in the walls of said chamber to supply heat to the work, said furnace being provided with a plurality of openings in the bottom thereof extending into the bottom of said chamber and spaced along the length thereof, elongated supporting members extending through said openings into said chamber, the work resting on the ends of said members, and means to rotate said members.

6. The combination of claim 5 including struc- REFERENCES CITED ure forming a second elongated furnace chamf ber above said first chamber, said structure being g g 3 g a fi are of record in the provided with openings between said chambers whereby products of combustion from the burners 6 UNITED STATES PATENTS in the first chamber can flow to the second to Number Name Date heat work therein, and means to convey Work 1363.236 Lavaud Sept. 4, 1923 through said second chamber. Lee Oct. 26, 1926 7. The combination of claim 6 in which the Sammis Nov. 8, 1932 structure forming said second chamber includes 10 2 Bidle Apr. 21, 1936 means forming a removable roof therefor, and POStleWaite D 0 in which the openings between said two cham- 3, Hall Apr. 1, 1941 bers are in axial alignment with the supporting $317,009 Wilson et a1 Oct. 20, 1943 members.

QUENTIN M. BLOOM. l6 

